I don't quite remember from the original white paper if it was pushed as a feature or just a property of the system. But later proponents certainty try to say it is some revolutionary feature.

Now don't get me wrong. Transparency in the financial system is good. But a public blockchain as is, does not provide any transparency at all.

Now that I am thinking about it, they probably mean something else entirely by transparency. They probably mean, they know the total amount of BTC out there.